Favourable Conditions for the Removal of BOD and COD in Municipal Wastewater by Electrocoagulation

The objective of this study was to evaluate the influence of electrocoagulation conditions on the removal of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in municipal wastewater from the district of Cascas, in line with Sustainable Development Goal 6: Clean Water and Sanitation. A quantitative applied approach was adopted, using an experimental factorial design. Wastewater samples were collected from key points in the sewerage system and treated in electrochemical cells using aluminium (Al), iron (Fe) and combined Fe-Al electrodes. Three voltage levels (10.3 V, 20.2 V and 30.1 V) and three times (10, 20 and 40 min) were evaluated. The highest removal efficiencies were achieved with the Al-Fe electrode at 30.1 V and 40 min, reaching 96% BOD and 97% COD removal. The results demonstrate that electrode type, voltage and treatment time significantly affect contaminant removal. Thus, electrocoagulation is confirmed as a highly effective and low-cost technology for municipal wastewater treatment, with a strong potential for implementation in areas lacking adequate sanitary infrastructure.